Methods for static objects have in principle been disclosed under the term “3-D filtered back-projection”. A disadvantage with these methods is that redundant data which result from spiral scans with a small incremental table feed, owing to multiple exposure of the same voxel, are not used. The consequence of this is that the radiation dose administered to the object to be examined is used only incompletely for the imaging. There are also problems in connection with carrying out image reconstruction methods in such a way that a large number of provisional images are calculated by “2D filtered back-projection” from output data which come from focal track sections that are insufficient for the image reconstruction per se; only in a second step are the provisional images reformatted to form a definitive sectional image. These 2D methods are less useful for detector arrays with a large width, i.e. a large extent in the direction of the system axis, because an extremely large number of provisional images then need to be processed, which is problematic even when a large computing power is available.
Cardio CT devices are in principle also generally known which produce sectional recordings of periodically moved objects to be examined, such as the human heart, by registering the movement phases of the heart and by only using data which correlate with particular movement phases or movement states to produce the sectional images. A disadvantage with the known cardio CT devices, however, is that they are only usable for detectors with a comparatively small number of rows, or a small extent of the detector in the system axis direction, since they do not take into account the conical ray profile in the object to be examined.
Reference will be made to the Applicant's German patent application DE 101 59 927.7, not yet published at the priority date of the present application and the contents of which are incorporated by reference herein in their entirety, which describes a similar method and CT device but which relates only to the imaging of static objects to be examined. The disclosure content of this application is fully included here.